Uplink control information transmission method and apparatus for use in cellular mobile communication system

ABSTRACT

A communication method and apparatus of a terminal in a mobile communication system are provided. The communication method includes generating uplink control information for at least one activated cell; configuring, if the activated cell belongs to a Master Cell Group (MCG) under a control of a Master evolved Node B (MeNB), an uplink control channel based on the uplink control information of the activated cell belonging to the MCG; and transmitting the uplink control channel to a Primary Cell (PCell).

PRIORITY

This application is a Continuation Application of U.S. patentapplication Ser. No. 15/704,870, which was filed in the United StatesPatent and Trademark Office on Sep. 14, 2017, which is a ContinuationApplication of U.S. patent application Ser. No. 14/608,916, which wasfiled in the United States Patent and Trademark Office on Jan. 29, 2015,and claims priority under 35 U.S.C. § 119(a) to Korean PatentApplication No. 10-2014-0011599, which was filed in the KoreanIntellectual Property Office on Jan. 29, 2014, the entire content ofeach of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to a cellular mobilecommunication system and, more particularly, to an uplink controlinformation transmission method and apparatus of a User Equipment (UE)for use in the cellular mobile communication supporting inter-evolvedNode B (eNB) carrier aggregation.

2. Description of the Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission distance, the beamforming, massive Multiple-inputMultiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques are discussed in5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud RadioAccess Networks (RANs), ultra-dense networks, Device-to-Device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, Coordinated Multi-Points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and SlidingWindow Superposition Coding (SWSC) as an Advanced Coding Modulation(ACM), and Filter Bank Multi Carrier (FBMC), Non-Orthogonal MultipleAccess (NOMA), and. Sparse Code Multiple Access (SCMA) as an advancedaccess technology have been developed.

Meanwhile, mobile communication systems have evolved to includehigh-speed, high-quality wireless packet data communication systemscapable of providing data and multimedia services beyond earlyvoice-oriented services.

Recently, standardization organizations, such as the 3^(rd) GenerationPartnership Project (3GPP), the 3^(rd) Generation Partnership Project-2(3GPP2), and the Institute of Electrical and Electronics Engineers(IEEE), have standardized mobile communication systems (e.g., High SpeedDownlink Packet Access (HSDPA), Long Term Evolution (LTE), andLTE-Advanced (LTE-A) (3GPP), High Rate Packet Data (HRPD) and UltraMobile Broadband (3GPP2), and 802.16e (IEEE)) to meet requirements ofhigh-speed, high-quality wireless packet data communication services.

The LTE system, as a representative example of broadband radiocommunication systems, uses Orthogonal Frequency Division Multiplexing(OFDM) in downlink communications and Single Carrier Frequency DivisionMultiple Access (SC-FDMA) in uplink communications. In such a multipleaccess scheme, the time-frequency resources are allocated to carryuser-specific data and control information without overlap (i.e.maintaining orthogonality), so as to distinguish among user-specificdata and control information.

FIG. 1 is a diagram illustrating a basic structure of uplinktime-frequency resource grid for use in an LTE system.

FIG. 1 shows the basic time-frequency resource grid structure of theradio resource for data and/or control information in the uplink of anLTE system. In the LTE system of FIG. 1, the UpLink (UL) denotes theradio link for a User Equipment (UE) to transmit data and/or controlsignals to the evolved Node B (eNB), and the DownLink (DL) denotes theradio link for the eNB to transmit data and/or control signals to theUE.

In FIG. 1, the horizontal axis denotes time, and the vertical axisdenotes frequency. The smallest transmission unit in the time domain isan SC-FDMA symbol, and, N_(symb) SC-FDMA symbols 102 form a slot 106.Two slots 104 form a subframe, and 10 subframes 105 form a radio frame107. A slot 106 spans 0.5 ms, a subframe 105 spans 1.0 ms, and a radioframe 107 spans 10 ms. The smallest transmission unit in the frequencydomain is a subcarrier.

In the time-frequency domain, the basic resource unit is resourceElement (RE) 112, and each RE is defined by one SC-FDMA symbol index andone subcarrier index. A Resource Block (RB) or Physical Resource Block(PRB) 108 is defined by N_(symb) consecutive SC-FDMA symbols in the timedomain and N^(RB) _(SC) consecutive subcarriers in the frequency domain.Typically, the smallest data transmission unit is RB 108, and the systemtransmission band includes N_(RB) RBs. The system transmission bandincludes N_(RB)×N^(RB) _(SC) subcarriers. In the LTE system, N_(symb)=7and N^(RB) _(SC)=12 in general, but the numbers of symbols andsubcarriers included in the RB may change.

Meanwhile, the LTE system may use an Adaptive Modulation and Coding(AMC) scheme and channel sensitive scheduling as techniques forimproving the transmission efficiency.

The AMC scheme allows the sender to adjust a transmission data amount inadaptation to channel conditions, For example, when channel conditionsare poor, the sender decreases the transmission data rate, so as tomaintain the received signal error probability at an intended level. Bycontrast, when the channel conditions are good, the sender increases thetransmission data rate to transmit large amount information efficiently,while maintaining the received signal error probability at an intendedlevel.

Meanwhile, channel sensitive scheduling allows a sender to selectivelyserve a user having the best channel conditions from among a pluralityof users, so as to increase the system throughput, as compared toallocating a channel fixedly to serve a single user. Such an increase ofsystem throughput is referred to as multi-user diversity gain.

The AMC and channel sensitive scheduling are methods of adopting thebest modulation and coding scheme at the most efficient times, based onthe partial channel state information fed back from the receiver.

When using AMC along with a Multiple Input Multiple Output (MIMO)transmission scheme, it may be necessary to include the function ofdetermining a number of spatial layers or rank and precoder. In thiscase, the sender determines the optimal data rate, in consideration ofthe number of layers for use in MIMO transmission, as well as a codingrate and modulation scheme.

In order to support the AMC operation, the UE reports Channel StateInformation (CSI) to the eNB. The CSI includes at least one of ChannelQuality Indicator (CQI), Precoding Matrix Indicator (PMI), and RankIndicator (RI). The CQI indicates the Signal to Interference and NoiseRatio (SINR) on the whole system band (wideband) or part of the systemband (subband). Typically, the CQI is expressed in the form ofModulation and Coding Scheme (MCS) to meet a predetermined datareception performance. The PMI provides the eNB with precodinginformation necessary for multi-antenna data transmission in the MIMOsystem. The RI provides the eNB with the rank information necessary formulti-antenna transmission in the MIMO system. The CSI is transmitted bythe UE to assist the eNB to make a scheduling decision, but the MCS,precoding, and rank values to be applied for real data transmission aredetermined by the eNB.

At this time, the UE may transmit the CSI periodically at an intervalagreed with the eNB. This is referred to a ‘periodic CSI reporting’. TheeNB provides the UE with the control information required for a‘periodic CSI report’, such as CSI transmission cycle and CSItransmission resources, in advance. When using periodic CSI reporting,the UE sends, to the eNB, the CSI through an uplink control channel(i.e., a Physical Uplink Control Channel (PUCCH)). In an exceptionalcase where an uplink data channel (i.e., a Physical Uplink SharedChannel (PUSCH)) must be transmitted at the CSI transmission occasionfor the periodic CSI reporting, the UE multiplexes the CSI and theuplink data onto the PUSCH.

Unlike periodic CSI reporting, the eNB may request the UE for ‘aperiodicCSI reporting’, if necessary. The eNB notifies the UE of the aperiodicCSI reporting request control information through the control channel ofscheduling uplink data of the UE. If the aperiodic CSI reporting requestis received, the UE reports CSI to the eNB through the PUSCH.

The LIE system adopts Hybrid Automatic Repeat reQuest (HARQ) forretransmission of initial transmission data that has not beensuccessfully decoded. In the HARQ mechanism, if a receiver fails todecode the received data correctly, the receiver sends, to thetransmitter, a HARQ Negative Acknowledgement (HARQ NACK) to notify thetransmitter of the decoding failure, such that the transmitterretransmits the corresponding data on the physical layer. The receivercombines the retransmitted data and the decoding-failed data to increasethe data reception success probability. When the data decoding issuccessful, the receiver sends, to the transmitter, a HARQAcknowledgement (HARQ ACK) to request transmission of new data.

The control information, such as HARQ ACK/NACK and CSI, which the UEfeeds back to the eNB is called Uplink Control Information (UCI). In theLTE system, the UCI is transmitted to the eNB through a dedicated uplinkcontrol channel (i.e., a Physical Uplink Control Channel (PUCCH)). TheUCI also may be multiplexed with the data onto a dedicated uplink datachannel (i.e., a Physical Uplink Shared Channel (PUSCH)), transmitted tothe eNB.

In a broadband wireless communication system, one of the significantfactors to provide high-speed wireless data service is bandwidthscalability for dynamic resource allocation. For example, Long TermEvolution (LTE) system can support the bandwidths of 20/15/10/5/3/1.4MHz. The carriers can provide services with at least one of thebandwidths, and the user equipment can have different capabilities, suchthat some support only 1.4 MHz bandwidth and others support up to 20 MHzbandwidth.

In an LTE-Advanced (LTE-A) system, aiming to achieve the requirements ofthe International Mobile Telecommunications (IMT)-Advanced service canprovide broadband service by aggregating carriers up to 100 MHz. TheLTE-A system needs bandwidth wider than that of LTE systems forhigh-speed data transmission. Simultaneously, the LTE-A system must bebackwards compatible with the LTE system, such that LTE UEs can accessthe services of the LTE-Advanced system. For this purpose, the entiresystem bandwidth of the LTE-A system is divided into sub-bands orcomponent carriers that have a bandwidth supporting transmission orreception of the LTE UE and can be aggregated for supporting the highspeed data transmission of the LTE-A system in thetransmission/reception process of the legacy LTE system per componentcarrier.

FIG. 2 is a schematic diagram illustrating an LTE-A radio access systemsupporting carrier aggregation.

FIG. 2 shows an example of an evolved Node B (eNB) that aggregates twocomponent carriers (CC#1 and CC#2) having center frequencies at f1 andf2 respectively, In FIG. 2, the two component carriers CC#1 and CC#2 areconfigured with respect to the same eNB 102. The eNB 102 has coverageareas 104 and 106 corresponding to the respective component carriers. Inan LTE-A system capable of carrier aggregation, the data and controlinformation for the data communication are transmitted per componentcarrier. The network configuration of FIG. 2 is applicable for uplinkcarrier aggregation, as well as downlink carrier aggregation.

In the carrier aggregation-enabled system, the component carriers aresorted into a Primary Cell (PCell) and a Secondary Cell (SCell). ThePCell is responsible for allocating radio resource to the UE and worksas an anchor cell for initial attach and handover of the UE. The PCellis configured with a downlink primary frequency (or Primary ComponentCarrier (PCC) and an uplink primary frequency. The UE sends the UCIincluding the control information such as HARQ ACK/NACK and CSI to theeNB through the PUCCH, which is transmitted only in the PCell.

Meanwhile, the SCell is the cell that provides the UE with additionalradio resources in addition to the PCell and is configured with adownlink secondary frequency (or Secondary Component Carrier (SCC)) andan uplink secondary frequency, or only with the downlink secondaryfrequency. Unless otherwise stated, the terms ‘cell’ and ‘componentcarrier’ are used interchangeably.

In the legacy carrier aggregation-enabled LTE-A system, however, thecarrier aggregation is limited to intra-eNB carriers.

SUMMARY OF THE INVENTION

The present invention has been made to address at least the aboveproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present inventionprovides an uplink control information transmission method of a UE in amobile communication system.

Another aspect of the present invention provides an uplink controlinformation transmission method and apparatus of a UE that is capable offacilitating inter-eNB carrier aggregation in a mobile communicationsystem.

According to an aspect of the present invention, a communication methodof a terminal for use in a mobile communication system is provided. Thecommunication method includes generating uplink control information forat least one activated cell; configuring, if the activated cell belongsto a Master Cell Group (MCG) under a control of a Master evolved Node B(MeNB), an uplink control channel based on the uplink controlinformation of the activated cell belonging to the MCG; and transmittingthe uplink control channel to a Primary Cell (PCell).

According to another aspect of the present invention, a communicationmethod of a base station for use in a mobile communication system isprovided. The communication method includes determining whether one cellgroup or a plurality of cell groups are configured with respect to aterminal; and receiving, if the plurality of cell groups are configuredwith respect to the terminal, uplink control information from/through atleast one of a Primary Cell (PCell) and a primary Secondary Cell(pSCell).

According to another aspect of the present invention, a terminal of amobile communication system is provided. The terminal includes atransceiver configured to transmits and receives signals to and from anevolved Node B (eNB); and a controller configured to control to generateuplink control information for at least one activated cell, configures,if the activated cell belongs to a Master Cell Group (MCG) under acontrol of a Master eNB (MeNB), an uplink control channel based on theuplink control information of the activated cell belonging to the MCG,and to control the transceiver to transmit the uplink control channel toa Primary Cell (PCell). According to still another aspect of the presentinvention, a base station of a mobile communication system is provided.The base station includes a transceiver configured to transmit andreceive signals to and from a terminal; and a controller configured todetermine whether one cell group or a plurality of cell groups areconfigured with respect to a terminal and to control the transceiver toreceive, if the plurality of cell groups are configured with respect tothe terminal, uplink control information from/through at least one of aPrimary Cell (PCell) and a primary Secondary Cell (pSCell).

According to another aspect of the present invention, a communicationmethod of a terminal for use in a mobile communication system isprovided. A communication method is provided for a terminal in a mobilecommunication system. The communication method includes acquiringinformation for configuring at least one of a first cell group and asecond cell group; receiving scheduling information on a first subframeof the first cell group, the scheduling information comprising a channelstate information (CST) request; acquiring aperiodic CSI for a firstcell, wherein the first cell is one cell among at least one cell of thefirst cell group and the first cell is identified based on thescheduling information; acquiring periodic CSI for a second cell of thesecond cell group; and transmitting the aperiodic CSI for the first cellon a second subframe of the first cell in response to the CSI requestand transmitting the periodic CSI for the second cell on a thirdsubframe of the second cell, if the first cell group and the second cellgroup are different cell group.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentinvention will be more apparent from the following detailed description,taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating a basic structure of uplinktime-frequency resource grid for use in an LTE system;

FIG. 2 is a diagram illustrating an LTE-A radio access system supportingcarrier aggregation;

FIG. 3 is a diagram illustrating an example of a system architecture ofan inter-eNB carrier aggregation-enabled LTE-A system according to anembodiment of the present invention;

FIG. 4 is a signal flow diagram illustrating a control informationtransmission procedure according to an embodiment of the presentinvention;

FIG. 5 is a flowchart illustrating a UE-side procedure of a HARQACK/NACK transmission method according to a first embodiment of thepresent invention;

FIG. 6 is a flowchart illustrating a eNB-side procedure of the HARQACK/NACK transmission method according to the first embodiment of thepresent invention;

FIG. 7 is a flowchart illustrating the UE-side procedure according to analternative embodiment of the present invention modified from the firstembodiment of the present invention;

FIG. 8 is a flowchart illustrating a UE-side procedure according to analternative embodiment of the present invention modified from the firstembodiment of the present invention;

FIG. 9 is a flowchart illustrating a UE-side procedure of a CSItransmission method according to a second embodiment of the presentinvention;

FIG. 10 is a flowchart illustrating the UE-side procedure according toan alternative embodiment of the present invention modified from thesecond embodiment of the present invention;

FIG. 11 is a flowchart illustrating the UE-side procedure according toanother alternative embodiment of the present invention modified fromthe second embodiment of the present invention;

FIG. 12 is a flowchart illustrating the UE-side procedure of the HARQACK/NACK transmission method according to a third embodiment of thepresent invention;

FIG. 13 is flowcharts illustrating the UE-side procedure of the periodicCSI transmission method according to a fourth embodiment of the presentinvention;

FIG. 14 is a flowchart illustrating the eNB-side procedure of theperiodic CSI transmission method according to the fourth embodiment ofthe present invention;

FIG. 15 is a flowchart illustrating the UE-side procedure of the CSItransmission method according to a fifth embodiment of the presentinvention;

FIG. 16 is a flowchart illustrating the UE-side procedure of theaperiodic CSI transmission method according to a sixth embodiment of thepresent invention;

FIG. 17 is a diagram illustrating a concept of a PUCCH transmit powerdetermination method according to a seventh embodiment of the presentinvention;

FIG. 18 is a block diagram illustrating a configuration of a UEaccording to an embodiment of the present invention; and

FIG. 19 is a block diagram illustrating a configuration of an eNBaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, embodiments of the present invention are described withreference to the accompanying drawings in detail. The same or similarcomponents may be designated by the same or similar reference numeralsalthough they are illustrated in different drawings. Detaileddescriptions of constructions or processes known in the art may beomitted to avoid obscuring the subject matter of the present invention.

In the following description, a base station is an entity that allocatesresources to terminals, and may be any of, for example, an evolved NodeB (eNode B or eNB), a Node B, a Base Station (BS), a radio access unit,a base station controller, or a network node.

The terminal may be any of, for example, User Equipment (UE), a MobileStation (MS), a cellular phone, a smartphone, a computer, or multimediasystem equipped with a communication function. Although the followingdescription refers to Evolved-Universal Terrestrial Radio Access(E-UTRA) or LTE and Advance E-UTRA or LTE-A systems, embodiments of thepresent invention can be applied even to other communication systemshaving similar technical backgrounds and channel formats, with a slightmodification, without departing from the spirit and scope of embodimentsof the present invention.

An embodiment of the present invention provides an uplink controlinformation transmission method of a UE in an inter-eNB carrieraggregation-enabled LTE-A system.

An example of a system architecture of the inter-eNB carrieraggregation-enabled LTE-A system according to an embodiment of thepresent invention is described as follows.

FIG. 3 is a diagram illustrating an example of a system architecture ofthe inter-eNB carrier aggregation-enabled LTE-A system according to anembodiment of the present invention.

FIG. 3 shows an example of a system in which a plurality pico eNBs 303,305, and 307 having small coverage areas are distributed within thecoverage 302 of a macro eNB 301. Typically, a macro eNB transmitssignals at a power level greater than that of a pico eNB. The macro eNB301 and the pico eNBs 303, 305, and 307 are connected each other with acertain amount of backhaul delay. Accordingly, according to someembodiments of the present invention, delay-sensitive information is notexchanged between macro and pico eNBs.

Although the following description of embodiments of the presentinvention refers to carrier aggregation between macro eNB 301 and picoeNBs 303, 305, and 307, the present invention is not limited thereto,but can be applied for the carrier aggregation betweengeographically-remote eNBs. For example, embodiments of the presentinvention can be applied to carrier aggregation between twogeographically-remote macro eNBs and between two geographically-remotepico eNBs. Also, there is no limit in the number of carriers to beaggregated.

The embodiment of FIG. 3 is directed to a case where the macro eNB 301uses frequency f1 for downlink signal transmission, and the pico eNBs303, 305, and 307 use frequency f2 for downlink transmission. The macroeNB 301 transmits data or control information to the UE 309 through thefrequency f1, and the pico eNBs 303, 305, and 307 transmit data orcontrol information to the UE 309 through the frequency f2. Throughcarrier aggregation, multiple eNBs can transmit signals to the UEsimultaneously through multiple frequencies, resulting in an improvementof peak data rate and system throughput. In the environment shown anddescribed with reference to FIG. 3, the UE operation of communicatingwith the macro eNB 301 and the pico eNBs 303, 305, and 307 is calledDual Connectivity (DC).

The network configuration of FIG. 3 can be applied to uplink carrieraggregation as well as downlink carrier aggregation. For example, the UE309 may transmit data or control information to the macro eNB 301through frequency f1′. The UE 309 may also transmit data and controlinformation to the pico eNBs 303, 305, and 307 through f2′. Thefrequency f1′ corresponds to the frequency f1, and the frequency f2′corresponds to frequency f2.

When it is necessary for the UE to transmit uplink control informationcorresponding to the respective cells to the eNB through PUCCH in theintra-eNB carrier aggregation system shown in FIG. 2, the UE configuresone PUCCH corresponding to multiple cells which is transmitted through apredetermined uplink component carrier (e.g., PCell). In this case, itis possible to maintain the consistency of the UE and eNB operations fordelivering the uplink control information from the UE to the eNBindependently of the uplink carrier aggregation capability of the UE.Since the aggregated cells are under the control of one eNB, the eNB isable to acquire the uplink control informations for the respective cellsfrom the PUCCH transmitted by the UE through a single uplink componentcarrier and schedules the cells based thereon from the viewpoint of theeNB without any problems.

When using the inter-eNB carrier aggregation system of FIG. 3 (assumingthat there are two eNBs, i.e. eNB A and eNB B, involved in the inter-eNBcarrier aggregation), if the uplink control information transmission islimited to one uplink component carrier, the eNB A receiving the uplinkcontrol information through the uplink component carrier may use onlythe uplink control information of its own uplink component carrier(s)but not the uplink control information of the uplink componentcarrier(s) of the eNB B. Therefore, there is a need for a procedure fortransmitting the uplink control information of the uplink componentcarrier(s) of the eNB B from the eNB A to the eNB B through a backhaul.In this case, the backhaul delay makes difficult to schedule the cellsunder the control of the eNB B, resulting in degradation of systemefficiency.

A procedure for transmitting eNB-specific uplink control informationsfrom the UE to the eNBs in the inter-eNB carrier aggregation system isdescribed in detail later herein. Certain terms used frequently in thefollowing description of embodiments of present invention are definedbelow.

-   -   Dual Connectivity (DC): Operation in which a UE attaches to        multiple eNBs (e.g., Master eNB (MeNB) and Secondary eNB (SeNB))        to use their radio resources and there is some backhaul delay        between the MeNB and SeNB.    -   MeNB: eNB that acts as a mobility anchor for UE in DC mode.    -   SeNB: eNB providing additional radio resources for the UE in DC        mode, i.e., an eNB that is not an MeNB.    -   Master Cell Group (MCG): Group of serving cells associated with        the MeNB, which includes one PCell and one or more SCells.    -   Secondary Cell Group (SCG): Group of serving cells associated        with SeNB that includes one pSCell and one or more SCells.    -   primary Secondary cell (pSCell): Cell for PUCCH transmission of        a UE among the SCells associated with an SeNB

FIG. 4 is a signal flow diagram illustrating a control informationtransmission procedure according to an embodiment of the presentinvention.

Referring to FIG. 4, the UE 408 may transmit HARQ ACK/NACK aseNB-specific uplink control information on a PUCCH in a DC operation. InFIG. 4, the control information transmission is performed in theinter-eNB carrier aggregation system as shown in FIG. 3. FIG. 4 isdirected to an example in which the MeNB 402 controls the PCell 406 andthe SCell 404, and in which the SeNB 410 controls the pSCell 412 and theSCell 414.

In a first scenario according to FIG. 4, the UE 408 receives PDSCHs fromthe cells under the control of the MeNB 402 at a certain time point. Inthis case, the UE 408 sends the PCell 406 of the MeNB 402 the HARQACK/NACKs corresponding to the PDSCHs on PCell PUCCH. For example, theUE 408 receives a PDSCH from the SCell 404 of the MeNB 402 at subframe#n1, at step 416, and another PDSCH from the PCell 406 of the MeNB 402at subframe #n1, at step 418. Then, the UE 408 sends the PCell 406 ofthe MeNB 402 the HARQ ACK/NACKs corresponding to the PDSCHs receivedfrom the PCell 406 and SCell 404 of the MeNB 402 on the PCell PUCCH atsubframe #n1+k, at step 420. Here, k denotes a number of subframes forsecuring the time necessary for PDSCH reception/decoding and HARQACK/NACK generation of the UE. For example, k is set to a valuecorresponding to 4 subframes.

In a second scenario according to FIG. 4, the UE 408 receives PDSCHsfrom the cells under the control of the SeNB 410 at a certain timepoint. In this case, the UE 408 sends the pSCell 412 of the SeNB 410 theHARQ ACK/NACKs corresponding to the PDSCHs on the pSCell PDCCH. Forexample, the UE 408 receives a PDSCH from the pSCell 412 of the SeNB 410at subframe #n2, at step 422, and another PDSCH from the from the SCell414 of the SeNB 410 at subframe #n2, at step 424. Then, the UE 408 sendsthe pSCell 412 of the SeNB 410 the HARQ ACK/NACKs corresponding to thePDSCHs received from the pSCell 412 and SCell 414 on the pSCell PUCCH atsubframe #n2+k, at step 426. Here, k denotes a number of subframes forsecuring the time necessary for PDSCH reception/decoding and HARQACK/NACK generation of the UE. The value k may be set to a valuecorresponding to 4 subframes.

In third scenario according to FIG. 4, the UE 408 receives PDSCHs from acell under the control of the MeNB 402 and a cell under the control ofthe SeNB 410 at a certain time point. In this case, the UE 408 sends thePCell 406 of the MeNB 408 the HARQ ACK/NACK corresponding to the PDSCHreceived from the MeNB 402 on the PCell PUCCH and sends the pSCell 412of the SeNB 410 the HARQ ACK/NACK corresponding to the PDSCH receivedfrom the SeNB 410 on the pSCell PUCCH. For example, the UE 408 receivesa PDSCH from the PCell 406 of the MeNB 402 at subframe #n3, at step 428,and another PDSCH from the pSCell 412 of the SeNB 410 at subframe #n3,at step 432. Then the UE 408 sends the PCell 406 of the MeNB 402 theHARQ ACK/NACK corresponding to the PDSCH received from the PCell 406 onthe PCell PUCCH at subframe #n3+k, at step 430, and sends the pSCell 434of the SeNB 410 the HARQ ACK/NACK corresponding to the PDSCH receivedfrom the pSCell 412 on the pSCell PUCCH at subframe #n3+k, at step 434.

Uplink control information transmission methods according to theembodiments of the present invention are described hereinafter indetail.

First Embodiment

A first embodiment of the present invention is directed to a method fora UE to transmit HARQ ACK/NACK on PUCCH in the system supportinginter-eNB carrier aggregation between the first and second eNBs. In thefollowing example, the first eNB is the MeNB and the second eNB is theSeNB.

A UE-side procedure of HARQ ACK/NACK transmission method according tothe first embodiment of the present invention is described withreference to FIG. 5.

FIG. 5 is a flowchart illustrating a UE-side procedure of a HARQACK/NACK transmission method according to the first embodiment of thepresent invention.

Referring to FIG. 5, the UE receives a PDSCH from at least one activatedcell of the first and second eNBs, at step 502. The eNBs deactivate theSCells with the exception of the PCell and pSCell. At this time, the UEreceives data and control information through the activated cell otherthan the deactivated cell, in order to reduce power consumption.

Next, the UE decodes the received PDSCH(s) to determine whether totransmit HARQ ACK/NACK, at step 504. The UE determines whether theactivated cell in which the PDSCH(s) is received belongs to the MCG orthe SCG, at step 506.

If the activated cell belongs to the MCG, the UE generates a PUCCH withthe HARQ ACK/NACK for the activated cell of the MCG, at step 508. Then,the UE transmits the PUCCH to the PCell, at step 510.

Otherwise, if the activated cell belongs to the SCG, the UE generates aPUCCH with the HARQ ACK/NACK for the activated cell of the SCG, at step512. Then, the UE transmits the PUCCH to the pSCell, at step 514.

If it is determined that the activated cell includes an MCG cell and anSCG cell, at step 506, the UE performs all of the operations of steps508, 510, 512, and 514.

According to an alternative embodiment of the present invention, step506 may precede step 502.

An eNB-side procedure of a HARQ ACK/NACK transmission method accordingto the first embodiment of the present invention is described hereinwith reference to FIG. 6.

FIG. 6 is a flowchart illustrating the eNB-side procedure of the HARQACK/NACK transmission method according to the first embodiment of thepresent invention.

Referring to FIG. 6, the first and second eNBs determine whether theyhave configured multiple cell groups including one MCG and at least oneSCG to a UE, at step 602.

If the first and second eNBs have configured the multiple cell groups tothe UE, the first eNB receives a PUCCH from the UE through the PCell andthe second eNB receives a PUCCH from the UE through the pSCell, at step604.

If the first and second eNBs have not configured multiple cell groups tothe UE, the first eNB receives a PUCCH through the PCell, but the secondeNB does not receive a PUCCH from the UE.

The first embodiment of the present invention may be modified in variousways. Examples of embodiments of the present invention modified from thefirst embodiment of the present invention are described hereinafter withreference to FIGS. 7 and 8.

FIG. 7 is a flowchart illustrating a UE-side procedure according to analternative embodiment of the present invention modified from the firstembodiment of the present invention.

Referring to FIG. 7, the UE receives PDSCH(s) from at least oneactivated cell of the first and second eNBs, at step 702. The UE decodesthe received PDSCH(s) to determine whether to transmit HARQ ACK/NACK, atstep 704.

Next, the UE determines whether multiple cell groups including MCG andSCG are configured, at step 706.

If it is determined that multiple cell groups are configured, the UEgenerates per-cell group PUCCHs with per-cell group HARQ ACK/NACKs, atstep 708. Then, the UE transmits the MCG PUCCH through the PCell and theSCG PUCCH through the pSCell, at step 710.

If it is determined that one cell group is configured at step 706, theUE generates a PUCCH with the HARQ ACK/NACK corresponding to thereceived PDSCH and transmits the PUCCH through the PCell, at step 712.

FIG. 8 is a flowchart illustrating a UE-side procedure according to analternative embodiment of the present invention modified from the firstembodiment of the present invention.

Referring to FIG. 8, the UE determines whether multiple cells areconfigured by eNB(s), at step 802. The multiple cells may belong to thesame eNB or to different eNBs.

If it is determined that only one cell is configured, the UE receivesPDSCH from the corresponding cell, at step 814. Then, the UE decodes thereceived PDSCH to determine whether to transmit HARQ ACK/NACK, at step816. The UE generates PUCCH with HARQ ACK/NACK and transmits the PUCCHto the PCell at step 818.

If it is determined that multiple cells are configured at step 802, theUE receives PDSCH(s) from at least one activated cell of the first andsecond eNBs, at step 804. Then the eNB decodes the received PDSCH(s) todetermine whether to transmit HARQ ACK/NACKs, at step 806. Next, the UEdetermines whether multiple cell groups (including MCG and SCG) areconfigured by the eNBs, at step 808.

If it is determined that multiple cell groups are configured, the UEgenerates per-cell group PUCCHs with per-cell group HARQ ACK/NACKs, atstep 810. Next, the UE transmits the MCG PUCCH to the PCell and the SCGPUCCH to the pSCell, at step 812.

If it is determined that one cell group is configured, at step 808, theUE generates PUCCHs with HARQ ACK/NACKs corresponding to the receivedPDSCHs and transmits the PUCCHs to the PCell, at step 818.

Second Embodiment

The second embodiment of the present invention is directed to a methodfor a UE to transmit a CSI on PUCCH in a system supporting inter-eNBcarrier aggregation between the first and second eNBs. It is assumedthat the first eNB is the MeNB and the second eNB is the SeNB.

A UE-side procedure of a CSI transmission method according to the secondembodiment of the present invention is described with reference to FIG.9.

FIG. 9 is a flowchart illustrating the UE-side procedure of the CSItransmission method according to the second embodiment of the presentinvention.

Referring to FIG. 9, the UE performs CSI measurement on at least oneactivated cell of the first and second eNBs, at step 902.

The UE determines the CSI transmission timings for the respectiveactivated cells, at step 904. At this time, the eNB may send the UE thecontrol information related to CSI transmission in advance in order forthe UE to determine the CSI transmission timing based on the controlinformation. According to an alternative embodiment of the presentinvention, step 904 precedes step 902. More specifically, the CSItransmission timing for the activated cells may be determined before CSImeasurement on the activated cells.

Afterward, the UE determines whether the activated cell to which the UEtransmits the CSI belongs to the MCG or the SCG, at step 906.

If the activated cell to which the UE transmits the CSI belongs to theMCG, the UE generates a PUCCH with the CSI for the activated cell of theMCG at step 908. If the CSI transmission timings of a plurality ofactivated cells of the MCG are overlapped, the UE generates the PUCCHwith the CSI of one activated cell selected based on a priority of RI,PMI, wideband CQI, and subband CQI according to the CSI type. Forexample, if the CSI of the activated cell is RI and the CSI of theactivated cell B is wideband CQI, the UE may transmit the RI of theactivated cell A but drop the wideband CQI of the activated cell B. Ifthe CSI types of the activated cells A and B are equal in priority, theUE may transmit the CSI of the activated cell having the lower cellindex.

The UE transmits the PUCCH to the PCell, at step 910.

If the activated cell to which the UE transmits the CSI belongs to theSCG, the UE generates PUCCH with the CSI of the activated cell of theSCG, at step 912. If the CSI transmission timings of a plurality ofactivated cells of the SCG are overlapped, the UE generates the PUCCHwith the CSI of one activated cell selected based on the CSI type cellindex as described with reference to step 908. A further detaileddescription thereof is therefore omitted herein for clarity andconciseness.

The UE transmits the generated PUCCH to the pSCell, at step 914.

If it is determined that the activated cells include the MCG and SCGcells, at step 906, the UE performs all of the operations of steps 908,910, 912, and 914.

More specifically, the UE transmits the CSI for the activated cell ofthe MCG and the CSI for the activated cell of the SCG at the same time.However, the UE cannot transmit the CSIs for the active cells of the MCGor the SCG at the same time.

According to an alternative embodiment of the present invention, step906 may precede step 904.

The eNB-side procedure of the CSI transmission method according to thesecond embodiment of the present invention is identical to the eNB-sideprocedure according to the first embodiment of the present invention.Therefore, a further detailed description of the eNB-side procedure ofthe CSI transmission message is omitted herein for clarity andconciseness.

The second embodiment of the present invention may be modified invarious ways. Certain embodiments of the present invention modified fromthe second embodiment of the present invention are described hereinafterwith reference to FIGS. 10 and 11.

FIG. 10 is a flowchart illustrating the UE-side procedure according toan alternative embodiment of the present invention modified from thesecond embodiment of the present invention.

Referring to FIG. 10, the UE performs CSI measurement on one or moreactivated cells of the first and second eNBs at step 1002.

The UE determines the CSI transmission timings for the respectiveactivated cells at step 1004. At this time, the eNB may send the UE thecontrol information related to CSI transmission in advance in order forthe UE to determine the CSI transmission timing based on the controlinformation. According to certain alternative embodiments of the presentinvention, step 1004 may precede step 1002.

Afterward, the UE determines whether multiple cell groups including MCGand SCG are configured at step 1006. According to certain embodiments ofthe present invention, step 1006 may precede step 1002 or 1004.

If multiple cell groups are configured, the UE generates per-cell groupPUCCHs with CSIs for predetermined activated cell in the same cellgroup, at step 1008. As described with reference to step 908, the UE maydetermine the activated cell belonging to MCG or SCG for generatingPUCCH with the corresponding CSI.

The UE transmits the MCG PUCCH to the PCell and the SCG PUCCH to thepSCell, at step 1010.

If it is determined that one cell group is configured, at step 1006, theUE generates PUCCH with the CSI for one configured cell and transmitsthe PUCCH to the PCell, at step 1012.

FIG. 11 is a flowchart illustrating a UE-side procedure according toanother alternative embodiment of the present invention modified fromthe second embodiment of the present invention.

Referring to FIG. 11, the UE determines whether multiple cells areconfigured by eNB(s), at step 1102. The multiple cells may belong to thesame eNB or different eNBs.

If it is determined that a single cell is configured, the UE performsCSI measurement on the corresponding cell, at step 1114. The UEdetermines the transmission timing of the measured CSI, at step 1116.Then the UE generates PUCCH with the CSI and transmits the PUCCH to thePCell, at step 1118.

If it is determined that multiple cells are configured at step 1102, theUE performs CSI measurement on at least one activated cell, at step1104. Next, the UE determines the transmission timings of the measuredCSIs, at step 1106. The UE determines whether multiple cell groups(including MCG and SCG) are configured by the eNBs, at step 1108.

If multiple cell groups are configured, the UE generates per-cell groupPUCCHs with CSIs for predetermined activated cells in the same cellgroup, at step 1110. The activated cell (of MCG or SCG) of which CSI isto be configured onto a PUCCH is determined based on the CSI type andcell index as described herein with reference to step 908 of FIG. 9.Then, the UE transmits the MCG PUCCH to the PCell and the SCG PUCCH tothe pSCell.

If it is determined that one cell group is configured, at step 1108, theUE generates PUCCH with the CSI for one configured cell and transmitsthe PUCCH to the PCell, at step 1118.

Third Embodiment

The third embodiment of the present invention is directed to a methodfor the UE to transmit HARQ ACK/NACK on PUCCH in the system supportinginter-eNB carrier aggregation between the first and second eNBs. It isassumed that the first eNB is the MeNB and the second eNB is the SeNB.

A UE-side procedure of the HARQ ACK/NACK transmission method accordingto the third embodiment of the present invention is described withreference to FIG. 12.

FIG. 12 is a flowchart illustrating the UE-side procedure of the HARQACK/NACK transmission method according to the third embodiment of thepresent invention.

Referring to FIG. 12, the UE receives a PDSCH from the activated cell Aand PUSCH scheduling information from the activated cell B, at step1202. The PUSCH scheduling information is the control informationincluding the resource allocation information and MCS informationnecessary for PUSCH transmission of the UE. The PUSCH schedulinginformation is received from the eNB through the PUCCH. In the presentexample, the transmission timing of the HARQ ACK/NACK corresponding tothe PDSCH and the transmission timing of PUSCH based on the schedulinginformation received through PUSCH are identical to each other.

The UE decodes the received PDSCH to determine whether to transmit HARQACK/NACK, at step 1204. Next, the UE determines whether the cell groupof the activated cell A and the cell group of the activated cell B areidentical with each other, at step 1206.

If the cell groups of the activated cells A and B are identical witheach other, the UE determines the HARQ ACK/NACK payload size to beapplied to the transmission of the HARQ ACK/NACK corresponding to thePDSCH of the activated cell to be multiplexed on the PUSCH of theactivated cell B according to the number of cells configured in the cellgroup of the activated cell B and the transmission mode at step 1208.

At this time, the number of cells configured in the cell group for theterminal is set to a value according to the determination of the eNB.The eNB determines the number of activated cells to be configured in thecell group in the range of the number of cells configured in the cellgroup. At this time, the number of cells, which is determined in therange of the number of cell configured in the cell group, is a valuechanging less frequently than the number of activated cells.Accordingly, using the number of cells configured in the cell group asthe criterion for determining the HARQ ACK/NACK payload size of the UE,it is possible to reduce any misunderstanding about the HARQ ACK/NACKpayload between the eNB and the UE.

The transmission mode is determined depending on whether MIMOtransmission is enabled. In view of the HARQ ACK/NACK of the UE, theMIMO transmission mode requires a 2-bit HARQ ACK/NACK corresponding totwo codewords. Meanwhile, the non-MIMO transmission mode requires a1-bit HARQ ACK/NACK corresponding to one codeword. Accordingly, assumingthe number of cells configured for the MIMO transmission mode is C2 andthe number of cells configured for the non-MIMO transmission mode is C1(N=C1+C2), the HARQ ACK/NACK payload size of the UE becomes (C1+C2)*2.

Afterward, the UE multiplexes the HARQ ACK/NACK corresponding to thePDSCH of the activated cell A onto the PUSCH of the activated cell B andtransmits the PUSCH to the activated cell B, at step 1210.

If it is determined that the cell groups of the activated cells A and Bare different from each other, at step 1206, the UE generates a PUCCHwith the HARQ ACK/NACK corresponding to the PDSCH of the activated cellA and transmits the PUCCH to the cell group of the activated cell A andtransmits the PUSCH, as scheduled, to the activated cell B, at step1212.

If the PDSCH transmission and PUSCH scheduling are performedsimultaneously in the cell group of the activated cell A, and if thePDSCH transmission and PUSCH scheduling are performed simultaneously inthe cell group of the activated cell B, the UE multiplexes the HARQACK/NACK corresponding to the PDSCH transmitted in the cell group of theactivated cell A onto the PUSCH of the cell group of the activated cellA and multiplexes the HARQ ACK/NACK corresponding to the PDSCHtransmitted in the cell group of the activated cell B onto the PUSCH ofthe cell group of the activated cell B.

Fourth Embodiment

The fourth embodiment of the present invention is directed to a methodfor the UE to transmit a periodic CSI on a PUSCH in a system supportinginter-eNB carrier aggregation between the first and second eNBs. In thepresent example, the first eNB is the MeNB and the second eNB is theSeNB.

A UE-side procedure of a periodic CSI transmission method according tothe fourth embodiment of the present invention is described as followswith reference to FIG. 13.

FIG. 13 is a flowchart illustrating the UE-side procedure of theperiodic CSI transmission method according to the fourth embodiment ofthe present invention.

In the fourth embodiment of the present invention, it is assumed thatthe PUSCH transmission timing and multiple periodic CSI report timingsoverlap.

Referring to part (a) of FIG. 13, if a single cell group is configuredwith respect to the UE, the UE performs CSI measurement on multipleactivated cells for which the periodic CSI repotting transmissiontimings are overlapped, at step 1302.

Next, the UE multiplexes the CSIs for the multiple activated cells in anascending order of their cell indices, at step 1304.

Then the UE multiplexes the CSIs onto the PUSCH of the cell having theleast cell index among all of the activated cells having the scheduledPUSCHs, at step 1306.

Referring to part (b) of FIG. 13, if multiple cell groups are configuredwith respect to the UE, the UE performs CSI measurement on the multipleactivated cells of which periodic CSI reporting transmission timings areoverlapped, at step 1312.

Next, the UE multiplexes the CSIs of the activated cells in an ascendingorder of the cell indices per cell group, at step 1314. Then the UEmultiplexes the CSIs onto PUSCHs of the cells having the least cellindex among activated cells having the scheduled PUSCHs per cell group,at step 1316.

FIG. 14 is a flowchart illustrating an eNB-side procedure of theperiodic CSI transmission method according to the fourth embodiment ofthe present invention.

Referring to FIG. 14, an eNB determines whether multiple cell groups areconfigured with respect to the UE, at step 1402. It is possible todetermine whether multiple cell groups are configured through exchangeof cell group configuration information for the UE between the first andsecond eNBs.

If a single cell group is configured, the eNB managing the correspondingcell group acquires the CSI(s) from the PUSCH of a cell of thecorresponding cell group, at step 1404.

If multiple cell groups are configured, the eNB acquires CSIs from theper-cell group PUSCHs, at step 1406. If multiple PUSCHs are scheduled inone cell group, the eNB may receive the CSIs from the PUSCH of the cellhaving the least cell index.

Fifth Embodiment

The fifth embodiment of the present invention is directed to a UE-sideoperation when periodic CSI report timing and aperiodic CSI reporttiming are overlapped in the system supporting inter-eNB carrieraggregation between the first and second eNBs. In the present example,the first eNB is the MeNB and the second eNB is the SeNB.

A UE-side procedure of a CSI transmission method according to the fifthembodiment of the present invention is described with reference to FIG.15.

FIG. 15 is a flowchart illustrating the UE-side procedure of the CSItransmission method according to the fifth embodiment of the presentinvention.

Referring to FIG. 15, the UE determines that a periodic CSI reporttiming and an aperiodic CSI report timing are overlapped, at step 1502.The UE may determine the periodic CSI report timing based on the CSItransmission control information previously transmitted by the eNB. Theaperiodic CSI report timing occurs after a predetermined time (e.g., 4subframes) since the CSI report command has been transmitted from theeNB to the UE.

Next, the UE determines whether the periodic CSI report and aperiodicCSI report are the CSI reports for the same cell group, at step 1504.

If the periodic CSI reporting and aperiodic CSI reporting are scheduledfor the same cell group, the UE performs aperiodic CSI reporting throughthe PUSCH as scheduled by the eNB and skips the periodic CSI reportingat step 1506.

If it is determined that the periodic CSI reporting and the aperiodicCSI reporting are scheduled for different cell groups, at step 1504, theUE performs the periodic CSI reporting and the aperiodic CSI reportingto the respective cell groups, at step 1508.

Sixth Embodiment

The sixth embodiment of the present invention is directed to a UE-sideprocedure when multiple aperiodic CSI reporting commands are received inthe system supporting inter-eNB carrier aggregation between the firstand second eNBs. In the present example, the first eNB is the MeNB andthe second eNB is the SeNB.

The UE-side procedure of the aperiodic CSI transmission method accordingto the sixth embodiment of the present invention is described withreference to FIG. 16.

FIG. 16 is a flowchart illustrating the UE-side procedure of theaperiodic CSI transmission method according to the sixth embodiment ofthe present invention.

Referring to FIG. 16, the UE determines whether multiple cell groups areconfigured with respect to the UE, at step 1602.

If multiple cell groups are configured with respect to the UE, the UEmay receive aperiodic CSI reporting commands for the activated cellsbelonging to different cell groups at step 1604. That is, the UE mayreceive the aperiodic CSI reporting command for the activated cell ofthe MCG and the aperiodic CSI reporting command for the activated cellof the SCG simultaneously from the MeNB and SeNB.

If a single cell group is configured with respect to the UE, the UE doesnot receive multiple aperiodic CSI reporting commands at step 1606.

Seventh Embodiment

The seventh embodiment of the present invention is directed to a methodfor the UE to determine transmit powers per-eNB PUCCH in a systemsupporting inter-eNB carrier aggregation between the first and secondeNBs. In the present example, the first eNB is the MeNB and the secondeNB is the SeNB.

The PUCCH transmit power P_(PUCCH)(i, c) at subframe i of cell c isdetermined by Equation (1), as follows:

P_(PUCCH)(i,c)=min{P_(CMAX)(c)−P_(O_PUCCH)(c)+PL(c)+h(n_(CSI),h_(HARQ),n_(SR),c)+Δ_(F_PUCCH)(F,c)+Δ_(T×D)(F′,c)+g(i,c)}  (1)

In Equation (1):

-   -   P_(CMAX)(c): Maximum allowed UE transmit power for cell c which        is determined based on UE power class and higher layer signaling        configuration    -   P_(O_PUCCH)(c): UL interference compensation value which the eNB        measures for cell c and signals to UE.    -   PL(c): Pathloss between eNB and UE in cell c which is difference        between transmit power of Reference Signal (RS) transmitted by        eNB and received signal strength level of RS at UE.    -   h(n_(CSI), n_(HARQ), n_(SR), c): Offset value determined based        on control signal of PUCCH to be transmitted by UE in cell c. If        the control information is the CSI for a predetermined cell of        the cell group including cell c, n_(CQI) is determined based on        the number of bits of the CSI for the corresponding cell. If the        control information is the Scheduling Request (SR) for the cell        group including cell c, n_(SR) is determined based on the number        of bits of the SR. If the control information is the HARQ        ACK/NACK for a predetermined cell of the cell group including        cell c, n_(HARQ) is determined as follows:

$n_{HARQ} = {\sum\limits_{c = 0}^{N_{cells}^{DL} - 1}N_{c}^{received}}$

(here, N_(cells) ^(DL) denotes a number of cells configured in the cellgroup including cell c, and N_(c) ^(received) denotes a number ofTransport Blocks (TBs) received in the cell group including cell c atsubframe#(i−4).)

-   -   Δ_(F_PUCCH)(F,c): Offset configured by eNB depending on whether        control information which the UE wants to transmit on PUCCH for        cell c is HARQ ACK/NACK, CSI, or SR, and signaled to the UE.    -   Δ_(T×D)(F′,c): Value determined through higher layer signaling        according to whether transmit diversity is applied to PUCCH of        cell c.    -   g(i,c): Value calculated based on power control command for cell        c which is included in the PDSCH scheduling information or group        power control information for subframe i in the cell group        including cell c from the eNB.

When transmitting a HARQ ACK/NACK through PUCCH, the UE determines ULradio resources for PUCCH transmission at subframe i of cell c in atleast one reference cell (e.g., PCell and pSCell) in the cell groupincluding the cell c and transmits the PUSCH at the transmit powercalculated by equation (1). For example, if the UE received PDSCHs fromthe respective PCell of the MCG and pSCell of the SCG, the UE determinesthe PUCCH radio resource for PCell based on the PDCCH scheduling thePDSCH of the PCell and the PUCCH radio resource for pSCell based on thePDCCH scheduling PDSCH of the pSCell. More specifically, the UEdetermines the PUCCH radio resource for HARQ ACK/NACK transmission basedon at least one PDCCH received through the same cell group as the PUCCHbut ignores the PDCCH received through other cell group in determiningPUCCH radio resource determination.

When transmitting CSI through PUCCH, the UE may determine the CSItransmission radio resource signaled by the eNB in advance for the cellgroup including the cell c as the UL radio resource for PUCCHtransmission at subframe i of the cell c and transmit the PUCCH at thetransmit power calculated by Equation (1).

FIG. 17 is a diagram illustrating a concept of a PUCCH transmit powerdetermination method according to the seventh embodiment of the presentinvention.

Referring to FIG. 17, the PUCCH transmit power 1707 for cell c isdetermined based on HARQ ACK/NACKs, CSIs, and SRs 1701 for the cells inthe cell group including the cell c and the power control commands 1703for the cells in the cell group including the cell c, and otherparameters 1705.

FIG. 18 is a block diagram illustrating a configuration of a UEaccording to an embodiment of the present invention. In FIG. 18, certainwell-known functions and constructions of a UE are omitted for clarityand conciseness.

Referring to FIG. 18, a UE according to an embodiment of the presentinvention includes a transceiver including first and second transmitters1860 and 1865 and a controller 1810. The control unit 1810 controls theUE to perform the operations according to any of the above-describedembodiments of the present invention. The first transmitter 1860includes a first PUCCH block 1820, a first PUSCH block 1830, a firstmultiplexer 1840, and a first transmission Radio Frequency (RF) block1850, for transmission to a first eNB. The second transmitter 1865includes a second PUCCH block 1825, a second PUSCH block 1835, a secondmultiplexer 1845, and a second transmission RF block 1855, fortransmission to the second eNB. The controller 1810 may include acontrol information transmission controller. The control informationtransmission controller controls the function blocks of the transmittersfor transmitting uplink control informations of the UE based on thePDSCH and PUSCH scheduling informations received from the eNB. Asdescribed above, the control information transmission controller of theUE determines the uplink control information transmission operationdepending on the cell and cell group from which the PDSCH and/or PUSCHscheduling information is received.

The first and second PUCCH blocks 1820 and 1825 of the first and secondeNB-specific transmitters 1860 and 1865 perform channel coding andmodulation on the uplink control information including HARQ ACK/NACKs,CSIs, etc. to generate PUCCHs. The first and second PUSCH blocks 1830and 1835 perform channel coding and modulation on the uplink data togenerate PUSCHs. At this time, the PUSCHs may be configured with respectto include uplink control information under the control of the controlinformation transmission controller. The PUCCHs and PUSCHs generated bythe first and second PUCCH blocks 1820 and 1825 and the first and secondPUSCH blocks 1830 and 1835 are multiplexed by the first and secondmultiplexers 1840 and 1845, processed by the first and secondtransmission RF blocks 1850 and 1855, and then transmitted to the firstand/or second eNB.

FIG. 19 is a block diagram illustrating a configuration of an eNBaccording to an embodiment of the present invention. In FIG. 19, certainwell-known functions and constructions of an eNB are omitted for clarityand conciseness.

Referring to FIG. 19, the eNB according to an embodiment of the presentinvention includes a transceiver including a receiver 1960, a controller1910, and a scheduler 1970. The controller 1910 controls the eNB toperform the operations of any of the above described embodiments of thepresent invention. The receiver 1960 includes a PUCCH block 1920, aPUSCH block 1930, a demultiplexer 1940, and a reception RF block 1950.The controller 1910 may include an uplink control information receptioncontroller. The uplink control information reception controller managesthe uplink control information transmission resource per UE. The uplinkcontrol information reception controller controls the receptionoperation of the eNB when the UE transmits uplink control informationand the operations of scheduler 1970 and the function blocks of thereceiver 1960. The receiver 1960 of the eNB demultiplexes the signalreceived from the UE by the demultiplexer 1940 and transfers thedemultiplexed data to the PUSCH block 1920 and the PUSCH block 1930. ThePUCCH block 1920 performs demodulation and channel decoding on the PUCCHincluding the uplink control information of the UE to acquire HARQACK/NACK, CSI, etc. The PUSCH block 1930 performs demodulation andchannel decoding on the PUSCH including uplink data of the UE to acquireuplink data and uplink control information transmitted by the UE. Atthis time, the receiver 1960 of the eNB sends the outputs of the PUCCHand PUSCH blocks 1920 and 1930 to the scheduler 1970 and uplink controlinformation reception controller for scheduling process.

As described above, an uplink control information transmission methodaccording to embodiments of the present invention advantageouslytransmits uplink control information efficiently by use of an improveduplink control information transmission procedure and method of a UE.

While the present invention has been shown and described with referenceto certain embodiments thereof, it will be understood by those skilledin the art that various changes in form and detail may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims and their equivalents.

What is claimed is:
 1. A communication method of a terminal in a mobilecommunication system, the communication method comprising: acquiringinformation for configuring at least one of a first cell group and asecond cell group; receiving scheduling information on a first subframeof the first cell group, the scheduling information comprising a channelstate information (CSI) request; acquiring aperiodic CSI for a firstcell, wherein the first cell is one cell among at least one cell of thefirst cell group and the first cell is identified based on thescheduling information; acquiring periodic CSI for a second cell of thesecond cell group; and transmitting the aperiodic CSI for the first cellon a second subframe of the first cell in response to the CSI requestand transmitting the periodic CSI for the second cell on a thirdsubframe of the second cell, if the first cell group and the second cellgroup are different cell group.